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Re: Preprocessor arithmetic
>>>>> "Geoff" == Geoff Keating <geoffk@geoffk.org> writes:
Geoff> Mark Mitchell <mark@codesourcery.com> writes:
>> EDG's compiler uses arbitrary numbers of host words, and that
>> really is necessary. There are 32-bit chips without 64-bit
>> data types, that need to cross compile to 64-bit chips with
>> 128-bit data types. Whether we use gmp, or roll a small
>> library of our own, we need this functionality.
Geoff> Do we really support cross-compiling from any chip for
Geoff> which we don't support a 64-bit data type? I can't think
Geoff> of any.
I don't know.
I do recally having trouble building cross-compilers from IA32 to IA64
due to issues with 128-bit types -- but of course IA32 does have a
64-bit type.
In general, however, there are operations that we punt on because of
our HOST_WIDE_INT pairs (like, for example, printing out large numbers
in error messages), and GMP would solve all of those problems for us
rather tidily. It's possible that we could also make a version of GMP
that didn't allow *arbitrary* precision, but instead allowed just
enough. The point is that there are routines in there to do all kinds
of useful stuff that otherwise we have to reinvent inside the
compiler.
It's hard to know what the performance issues will mean until we
measure...
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com